c# 获取中国所有IP

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            DateTime start = System.DateTime.Now;
            List<something> soms = GetIp();
            DateTime end = System.DateTime.Now;
            WriteFile(soms);
            Console.WriteLine("执行时间为:" + (end - start).ToString("T"));
            Console.WriteLine("总IP数:" + soms.Count);
            Console.ReadLine();
        }
        //获取最新中国地区IPV4地址段
        public static List<something> GetIp()
        {

            HttpWebRequest request = (HttpWebRequest)WebRequest.Create("http://ftp.apnic.net/apnic/stats/apnic/delegated-apnic-latest");
            request.Host = "ftp.apnic.net";
            request.Accept = "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8";
            request.Headers.Add("Accept-Encoding", "gzip, deflate");
            request.Headers.Add("Accept-Language", "zh-CN,zh;q=0.9");
            request.Headers.Add("Cache-Control", "max-age=0");
            request.Headers.Add("Cookie", "__cfduid=dbbe005c7bff8939bd00da2e62711b7481547619516; _ga=GA1.2.332852563.1547619523; _gid=GA1.2.1547830089.1547619523");
            request.UserAgent = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/69.0.3497.100 Safari/537.36";
            HttpWebResponse response;
            response = (HttpWebResponse)request.GetResponse();
            Stream s;
            s = response.GetResponseStream();
            string encoding = response.ContentEncoding;
            if (encoding == null || encoding.Length < 1)
            {
                encoding = "UTF-8"; //默认编码
            }
            StreamReader reader = new StreamReader(response.GetResponseStream(), Encoding.GetEncoding(encoding));
            string retString = reader.ReadToEnd();
            int indexa = retString.IndexOf("2|");
            string end = retString.Remove(0, indexa + 2);
            string[] striparr = end.Split(new string[] { "\n" }, StringSplitOptions.None);
            List<something> soms = new List<something>();
            foreach (var item in striparr)
            {
                string[] i = item.Split('|');
                if (i.Length == 7 && i[1] == "CN" && i[2] == "ipv4")
                {
                    something som = new ConsoleApplication1.something();
                    som.org = i[0];
                    som.country = i[1];
                    som.type = i[2];
                    som.startIp = i[3];
                    som.ipCount = i[4];
                    som.setTime = i[5];
                    som.setType = i[6];
                    soms.Add(som);
                }
            }
            return soms;
        }

        public static void WriteFile(List<something> arr)
        {
            StreamWriter sw = new StreamWriter(@"\桌面\新建文件夹\ConsoleApplication1\IPS1.txt", true, System.Text.Encoding.Default);
            for (int i = 0; i < arr.Count; i++)
            {
                sw.WriteLine(arr[i].startIp);
                Console.WriteLine(arr[i].startIp);
            }

            sw.Close();
        }
    }
}